Shaving processing method and shaving processing apparatus for gear

ABSTRACT

A shaving processing method and apparatus for a gear are provided which reduce a load at the time of processing a tooth surface, thereby reducing a transmission error of the gear. Embodiments include a method for finishing the tooth surface of the gear in a state where the gear and a shaving cutter are engaged with each other and the shaving cutter is rotated. The gear has a pair of end surfaces facing each other in the tooth width direction. A first shaving step of processing the tooth surface is performed so that a processing region gradually expands from one end surface of the pair of end surfaces toward the other end surface, and a second shaving step of processing the tooth surface is performed so that a processing region gradually expands from the other end surface of the pair of end surfaces toward the one end surface.

TECHNICAL FIELD

The present disclosure relates to a shaving processing method and ashaving processing apparatus for a gear.

BACKGROUND ART

Japanese Patent Laid-Open No. 2004-154873 discloses a shaving processingmethod for finishing a tooth surface of a gear by using a shavingcutter. In this shaving processing method, so that an axis of the gearand an axis of the shaving cutter intersect with each other at apreviously determined intersection angle, the gear and the shavingcutter are disposed in a state of being engaged with each other, and theshaving cutter is rotated, thereby performing finishing processing ofthe tooth surface. However, when at the time of finishing processing, apreviously determined cut amount of the tooth surface is all cut inone-time processing, the processing load increases, thus easily causingan error. This error causes a transmission error in a rotational angleof the engaged gear, and an increased transmission error may causevibration and noise.

SUMMARY

The disclosure of the present application provides a shaving processingmethod and a shaving processing apparatus for a gear which reduce aprocessing load at the time of processing a tooth surface, and therebyreduce a transmission error of the gear.

A shaving processing method according to an embodiment of the presentdisclosure is a shaving processing method for finishing a tooth surfaceof a gear in a state where the gear and a shaving cutter are engagedwith each other and the shaving cutter is rotated, the gear comprising apair of end surfaces facing each other in a tooth width direction. Thedisclosed method has a first shaving step of processing the toothsurface so that a processing region gradually expands from one endsurface of the pair of end surfaces toward the other end surface, and asecond shaving step of processing the tooth surface so that a processingregion gradually expands from the other end surface of the pair of endsurfaces toward the one end surface.

Furthermore, a shaving processing apparatus according to an embodimentof the present disclosure is a shaving processing apparatus forfinishing a tooth surface of a gear in a state where the gear and ashaving cutter are engaged with each other and the shaving cutter isrotated, the gear comprising a pair of end surfaces facing each other ina tooth width direction. The disclosed apparatus includes anintersection angle adjusting mechanism which sets an intersection anglebetween a central axis of the gear and a central axis of the shavingcutter to a first intersection angle and to a second intersection anglecorresponding to a finishing condition of the tooth surface.

According to the present disclosure, finishing processing of the gear isdivided into the first shaving step and the second shaving step to beperformed. The first shaving step and the second shaving step bothprocess the tooth surface to gradually expand the processing regions. Atthis time, a processing load gently increases, so that the entireprocessing load is reduced. As a result, an error is suppressed, and agear with a reduced transmission error can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a shaving processing apparatus accordingto an embodiment of the present disclosure.

FIGS. 2A and 2B are plan views in which a shaving cutter and gear of theshaving processing apparatus shown in FIG. 1 are viewed from above.

FIG. 3 is a schematic view describing a shaving processing methodperformed by the shaving processing apparatus shown in FIG. 1.

FIG. 4 is a schematic view of a state where the shaving cutter and thegear are engaged with each other in the shaving processing method ofFIG. 3.

FIG. 5 is a perspective view of a tooth surface of the gear shown inFIG. 4.

FIGS. 6A and 6B are graphs describing a relationship between a positionof the cutter and a processing load in the shaving processing method ofFIG. 3.

FIGS. 7A and 7B are graphs describing a relationship between a positionof a cutter and a processing load in a conventional shaving processingmethod.

FIG. 8 is a graph of a transmission error of the gear obtained by theshaving processing method of FIG. 3.

FIGS. 9A-9B are schematic views of the cutter used in a shavingprocessing method of another disclosed embodiment.

DETAILED DESCRIPTION

Hereinafter, an embodiment of a shaving processing apparatus and shavingprocessing method according to the present disclosure will be describedwith reference to the attached drawings. Note that the shavingprocessing apparatus and shaving processing method of the embodimentdescribed below use a plunge cut shaving method in which a shavingcutter is caused to approach a workpiece gear to thereby process theworkpiece gear, but are not limited to this.

Configuration of Shaving Processing Apparatus

FIG. 1 is a schematic view of the shaving processing apparatus accordingto this embodiment. The size of the illustrated apparatus and the sizeand shape of each of portions constituting the apparatus are shown in anexaggerated manner and differ from the actual ones.

A shaving processing apparatus (hereinafter referred to as a “processingapparatus”) 100 shown in FIG. 1 has a workpiece gear supportingmechanism 10. The workpiece gear supporting mechanism 10 has a gearsupporting shaft 12 detachably supporting a workpiece gear 11. In thisembodiment, the gear supporting shaft 12 extends in the left-rightdirection of the drawing. A central axis 13 of the workpiece gear 11 anda central axis 14 of the gear supporting shaft 12 coincide with eachother in a state where the workpiece gear 11 is supported by the gearsupporting shaft 12. Hereinafter, the direction of the central axis 14of the gear supporting shaft 12 is referred to as an “x direction”; thefront-back direction of the drawing which is orthogonal to the xdirection, a “y direction”; the up-down direction of the drawing whichis orthogonal to the x direction and the y direction, a “z direction.”

Workpiece Gear Supporting Mechanism

The gear supporting shaft 12 is supported by a fixed base 15. The gearsupporting shaft 12 may be rotatably fixed to the fixed base 15 or maybe non-rotatably fixed to the fixed base 15. When the gear supportingshaft 12 is rotatably fixed to the fixed base 15, the workpiece gear 11may be rotatable or non-rotatable with respect to the gear supportingshaft 12. When the gear supporting shaft 12 is non-rotatably fixed tothe fixed base 15, the workpiece gear 11 is rotatable with respect tothe gear supporting shaft 12.

Cutter Driving Unit

The processing apparatus 100 also has a cutter driving unit 20. Thecutter driving unit 20 has a cutter supporting shaft 22 detachablysupporting a shaving cutter (hereinafter referred to as a “cutter”) 21.A central axis 23 of the cutter 21 and a central axis 24 of the cuttersupporting shaft 22 coincide with each other in a state where the cutter21 is supported by the cutter supporting shaft 22. The cutter supportingshaft 22 is held so that the central axis 23 of the cutter 21 and thecentral axis 24 of the cutter supporting shaft 22 are positioned on asurface parallel to an xy plane including the x direction and the ydirection.

Cutter Rotating Mechanism

The cutter supporting shaft 22 is supported by a cutter rotatingmechanism 31. The cutter rotating mechanism 31 has a cutter rotatingmotor 32, the cutter rotating motor 32 is drivingly connected to thecutter supporting shaft 22, and the cutter supporting shaft 22 isconfigured so as to rotate based on driving of the cutter rotating motor32.

Cutter Lifting and Lowering Mechanism

The cutter rotating mechanism 31 is supported so as to be capable oflifting and lowering, by a cutter lifting and lowering mechanism 33which moves or lifts and lowers the cutter rotating mechanism 31 in thez direction. In this embodiment, the cutter lifting and loweringmechanism 33 includes a cutter lifting and lowering motor 34, arotational axis (not illustrated) of the cutter lifting and loweringmotor 34 is drivingly connected to the cutter rotating mechanism 31, andthe cutter rotating mechanism 31 is configured to move or lift and lowerin the z direction based on driving of the cutter lifting and loweringmotor 34.

Cutter Turning Mechanism

The cutter lifting and lowering mechanism 33 is supported by a cutterturning mechanism (intersection angle adjusting mechanism) 35. In thisembodiment, the cutter turning mechanism 35 includes a cutter turningmotor 36, and the cutter rotating mechanism 31 and the cutter liftingand lowering mechanism 33 are configured so as to integrally turn andmove based on driving of the cutter turning motor 36 in a state where acenter 39 of the cutter 21 is positioned at a reference line 38 in the zdirection which passes through a center 37 of the workpiece gear 11supported by the gear supporting shaft 12 of the workpiece gearsupporting mechanism 10.

The cutter rotating motor 32, the cutter lifting and lowering motor 34,and the cutter turning motor 36 are rotatable in the forward and reversedirections. Alternatively, a mechanism which reverses the rotationaldirection may be provided in a mechanism which transmits the driving ofeach of the motors so that this reversing mechanism switches therotational direction and moving direction (lifting and loweringdirection and turning direction) of the cutter.

It is preferable that the cutter lifting and lowering motor 34 and thecutter turning motor 36 use a stepping motor to be able to strictlyadjust a lifting and lowering amount and a turning amount (turningangle).

Controller

The cutter rotating motor 32, the cutter lifting and lowering motor 34,and the cutter turning motor 36 are connected to a controller 40 and areconfigured so that, during shaving processing, the driving is controlledbased on an instruction output from the controller 40. Specifically, aprogram necessary for performing shaving processing described below isstored in the controller 40, and based on this program, the driving ofthe motors 32, 34, and 36 is controlled.

Shaving Processing

An embodiment will be described in which the processing apparatus 100including the above configurations is used and a tooth surface of theworkpiece gear 11 is subject to shaving processing.

Workpiece Gear

In this embodiment, the workpiece gear 11 is a spur gear and has aninner peripheral surface and an outer peripheral surface which arecentered on the central axis 13, and a pair of end surfaces 111 and 112facing to each other in the direction of the central axis 13 (toothwidth direction), and on the outer peripheral surface, a tooth(workpiece tooth) 113 (see FIG. 4) is formed which extends parallel tothe central axis 13 at a constant interval in the peripheral direction.

In a state where the center 37 of the workpiece gear 11 coincides withthe reference line 38, the workpiece gear 11 is detachably fixed to thegear supporting shaft 12 so as to be rotatable with respect to the gearsupporting shaft 12 or rotatable together with the gear supporting shaft12.

Cutter

The cutter 21 has an inner peripheral surface and an outer peripheralsurface which are centered on the central axis 23, and a pair of endsurfaces 211 and 212 facing each other and orthogonal to the centralaxis 23, and on the outer peripheral surface, a cutting tooth 213 isformed which extends in a helical shape at a constant interval in theperipheral direction (i.e., the cutter 21 of this embodiment is of ahelical gear type). As shown in FIGS. 2A-2B, a length 214 (substantiallycorresponding to an interval of the pair of end surfaces facing eachother) of the cutting tooth 213 which relates to the direction of thecentral axis 23 of the cutter 21 is sufficiently larger than a length114 of the workpiece tooth 113 which relates to the direction of thecentral axis 13 of the workpiece gear 11 and is determined so that, in ashaving processing state where the central axis 23 of the cutter 21 isinclined at a predetermined angle (intersection angles θ1 and 02described later) with respect to the central axis 13 of the workpiecegear 11 so as to intersect therewith, the cutting tooth 213 of thecutter 21 is engaged with the corresponding workpiece tooth 113 of theworkpiece gear 11 over the full length of the workpiece tooth 113 (seeFIG. 2).

In a state where the center 39 of the cutter 21 coincides with thereference line 38, the cutter 21 is detachably fixed to the cuttersupporting shaft 22.

Although in FIG. 1, the workpiece gear 11 and the cutter 21 arerepresented in a state of being engaged with each other, in a statebefore processing, the workpiece gear 11 and the cutter 21 are spacedapart from each other in the z direction. A position of the cutter 21 atthis time is an “initial position” of the cutter 21 (a position P0 inFIG. 6A), and shaving processing described below starts from thisinitial position.

First Shaving Step

The shaving processing is schematically divided into a first shavingstep and a second shaving step. In the first shaving step, thecontroller 40 drives the cutter turning motor 36 to set an intersectionangle (an intersection angle as viewed from the z direction) of thecentral axis 24 of the cutter supporting shaft 22 with respect to thecentral axis 14 of the gear supporting shaft 12 to the firstintersection angle θ1 (see FIG. 2A). The first intersection angle θ1 islarger than an intersection angle (second intersection angle θ2 shown inFIG. 2B) corresponding to a finishing condition for obtaining a toothsurface shape of the workpiece gear 11 which can be finally obtained.

The controller 40 next drives the cutter lifting and lowering motor 34for a predetermined time (from a time T0 to a time T1 in FIG. 6A) tocause the cutting tooth 213 of the cutter 21 to approach a tooth surface115 of the workpiece gear 11 (a cutter position P1 after the approach).

Subsequently, the controller 40, while driving the cutter rotating motor32 and thereby rotating the cutter 21, drives the cutter lifting andlowering motor 34 to cause the cutting tooth 213 of the cutter 21 toabut against the tooth surface 115 of the workpiece gear 11, therebyshaving the tooth surface 115 of the workpiece gear 11. A time at whichthe cutter 21 contacts the workpiece gear 11 is a time T12 in FIG. 6B.As shown in FIG. 6B, as the shaving of the cutter 21 increases, a loadapplied to the cutter 21 gradually increases. This load applied to thecutter 21 becomes constant immediately before the shaving of the cutter21 reaches a predetermined amount (a cutter position P2 in FIG. 6A).When the predetermined amount of the shaving ends, the controller 40stops the driving of the cutter lifting and lowering motor 34 (a time T2and the cutter position P2 in FIG. 6A).

As described above, in the first shaving step, the intersection angle ofthe central axis 24 of the cutter supporting shaft 22 with respect tothe central axis 14 of the gear supporting shaft 12 is set to the firstintersection angle θ1 which is larger than the second intersection angleθ2 corresponding to a final shape of the tooth surface 115.

Accordingly, as shown in FIG. 3, for example, at the tooth surface 115of the workpiece gear 11 contacting a driving-side cutting tooth surface215 (see FIG. 4) of the cutter 21, the shaving starts from a toothsurface portion 117 close to one end surface 111 of the workpiece gear11, and the shaving region (processing region) gradually expands towarda tooth surface portion 118 close to the other end surface 112.Conversely, at a tooth surface 116 of the workpiece gear 11 contacting adriven-side cutting tooth surface 216 (see FIG. 4) of the cutter 21, theshaving starts from a tooth surface portion 118′ close to the other endsurface 112 of the workpiece gear 11, and the shaving region (processingregion) gradually expands toward a tooth surface portion 117′ close tothe one end surface 111. Therefore, as shown in FIG. 6B, the load on thecutter 21 increases with an increase in the cut amount.

Furthermore, as shown in FIG. 3, at the tooth surface 115 of theworkpiece gear 11 contacting the driving-side cutting tooth surface 215(see FIG. 4) of the cutter 21, the tooth surface portion 117 close tothe one end surface 111 of the workpiece gear 11 is shaved deeper thanthe tooth surface portion 118 close to the other end surface 112, and atthe tooth surface 116 of the workpiece gear 11 contacting thedriven-side cutting tooth surface 216 (see FIG. 4) of the cutter 21, forexample, the tooth surface portion 118′ close to the other end surface112 of the workpiece gear 11 is shaved deeper than the tooth surfaceportion 117′ close to the one end surface 111.

Note that as shown in FIG. 3, in the first shaving step, a maximumshaved amount of the deeply shaved tooth surface does not reach a finalprocessing tooth surface (a tooth surface 119 after the secondprocessing).

Next, the controller 40, in a state of stopping the driving of thecutter lifting and lowering motor 34 and maintaining the cutter 21 atthe same position (the cutter position P2 in FIG. 6A), maintains thedriving of the cutter rotating motor 32 and executes a first dwell for apredetermined time (from the time T2 to a time T3). As shown in FIG. 6B,during this first dwell, the load applied to the cutter 21 decreases.

When the first dwell ends (the time T3 in FIG. 6A), the controller 40drives the cutter lifting and lowering motor 34 to slightly retract thecutter 21 from the workpiece gear 11 (a cutter position P3 in FIG. 6A).

A state where the cutter 21 is retracted from the workpiece gear 11 ismaintained for a predetermined time (from the time T3 to a time T4 inFIG. 6A). Meanwhile, the controller 40 drives the cutter turning motor36 to set the intersection angle of the central axis 24 of the cuttersupporting shaft 22 with respect to the central axis 14 of the gearsupporting shaft 12 to the second intersection angle θ2 which is smallerthan the first intersection angle θ1.

Second Shaving Step

Next, the second shaving step starts, and the controller 40, whiledriving the cutter rotating motor 32, drives the cutter lifting andlowering motor 34 (the time T4 and a cutter position P4 [=P3] in FIG.6A) to cause the cutter 21 to approach the workpiece gear 11 and causethe cutting tooth 213 of the cutter 21 to abut against the tooth surface115 of the workpiece gear 11, thereby shaving the tooth surface 115 ofthe workpiece gear 11. A time at which the cutter 21 contacts theworkpiece gear 11 is a time T45 in FIG. 6B.

At this time, as shown in FIG. 3, for example, at the tooth surface 115of the workpiece gear 11 contacting the driving-side cutting toothsurface 215 (see FIG. 4) of the cutter 21, the shaving starts from thetooth surface portion 118 close to the other end surface 112 of theworkpiece gear 11, and the shaving region (processing region) graduallyexpands toward the tooth surface portion 117 close to the one endsurface 111. Conversely, at the tooth surface 116 of the workpiece gear11 contacting the driven-side cutting tooth surface 216 (see FIG. 4) ofthe cutter 21, the shaving starts from the tooth surface portion 117′close to the one end surface 112 of the workpiece gear 11, and theshaving region (processing region) gradually expands toward the toothsurface portion 118′ close to the other end surface 111. Therefore, asshown in FIG. 6B, the load on the cutter 21 increases with an increasein the cut amount. This load applied to the cutter 21 becomes constantimmediately before the shaving of the cutter 21 ends (a cutter positionP5 in FIG. 6A).

Furthermore, as shown in FIG. 3, at the tooth surface 115 of theworkpiece gear 11 contacting the driving-side cutting tooth surface 215(see FIG. 4) of the cutter 21, the tooth surface portion 118 close tothe other end surface 112 of the workpiece gear 11 is more shaved thanthe tooth surface portion 117 close to the one end surface 111, and thefinal tooth surface (the tooth surface after the second processing) 119is completed. As shown in the drawing, in the final tooth surface 119,the tooth surface portion 117 close to the one end surface 111 of theworkpiece gear 11 and the tooth surface portion 118 close to the otherend surface 112 are shaved to the same degree, and the final toothsurface 119 is left-right symmetrical with respect to a midpoint betweenboth the end surfaces 111 and 112.

When the final tooth surface 119 of the workpiece gear 11 is completed(a time T5 and the cutter position P5 in FIG. 6A), the controller 40stops the driving of the cutter lifting and lowering motor 34.

During the second shaving step, the rotational direction of the cutterrotating motor 32 may be reversed. Thereby, left and right toothsurfaces of each of teeth of the workpiece gear 11 are processed moreequally.

Next, the controller 40, while stopping the driving of the cutterlifting and lowering motor 34, maintains the driving of the cutterrotating motor 32 and starts a second dwell (the time T5 and the cutterposition P5). The second dwell is continued for a predetermined time(from the time T5 to a time T6).

As required, the controller 40, while maintaining the driving of thecutter rotating motor 32, drives the cutter lifting and lowering motor34 to slightly retract the cutter 21 from the workpiece gear 11 (thetime T6 and a cutter position P6) and performs a third dwell. The thirddwell is continued for a predetermined time (from the time T6 to a timeT7).

Last, the controller 40 stops the driving of the cutter rotating motor32 and drives the cutter lifting and lowering motor 34 to return thecutter 21 to the initial position (the time T7 and the cutter positionP0).

As described above, in the shaving apparatus and the shaving methodaccording to the present embodiment, the shaving step is divided intothe first shaving step and the second shaving step. In the first shavingstep, the intersection angle between the gear central axis and thecutter central axis is set to the first intersection angle θ1 which islarger than the second intersection angle θ2 for final finishing and thepredetermined amount of the shaving is performed, and in the subsequentsecond shaving step, the intersection angle is set to the secondintersection angle θ2 for final finishing. Accordingly, in the first andsecond shaving steps, at each of the teeth of the workpiece gear, onetooth surface is gradually shaved from one end surface toward the otherend surface, and the other tooth surface is gradually shaved from theother end surface toward the one end surface. Accordingly, as apparentfrom FIG. 6B, a load which the cutter receives through the shavingmethod of this embodiment is less than a load received by a cutter in aconventional shaving method (a method in which a relationship between acut amount and a processing load is shown in FIGS. 7A-B) in which theintersection angle is set to an angle for final finishing (theabove-described second intersection angle) and the entire tooth surfaceis uniformly shaved.

Furthermore, since the load received by the cutter is reduced, as shownin FIG. 8, a transmission error of the gear processed by the shavingmethod according to this embodiment is smaller than a transmission errorof a gear processed by the conventional shaving processing method. As aresult, the gear processed by the shaving processing method of thisembodiment has further more improved power transmission efficiency anddurability than the gear processed by the conventional shavingprocessing method, reducing gear noise.

Other Embodiments

Although in the above description, the processing apparatus is providedwith the intersection angle adjusting mechanism (cutter turningmechanism) and, by this, the intersection angle is adjusted, theintersection angle between the central axis of the workpiece gearsupporting shaft and the central axis of the cutter supporting shaft maybe maintained constant, and the cutters used in the first shaving stepand the second shaving step may be switched. Furthermore, the firstintersection angle may be set according to a torsion angle of a cuttingtooth of a helical gear type cutter 21′ (see FIG. 9A) used in the firstshaving step, and the second intersection angle may be set according toa torsion angle of a cutting tooth of a helical gear type cutter 21″(see FIG. 9B) used in the second shaving step.

Furthermore, although in the above description, an embodiment isdescribed in which the first intersection angle θ1 is set to be largerthan the second intersection angle θ2, the first intersection angle maybe set to be smaller than the second intersection angle. In this case,the tooth surface after the first processing in FIG. 3 inclines in aleft and right reversed manner.

Furthermore, although in the above description, an embodiment isdescribed in which the workpiece gear is a spur gear and the cutter is ahelical gear type cutter, the present disclosure is also applicable to aprocessing apparatus and a processing method in which the workpiece gearis a helical gear and the cutter is a spur gear type cutter.Furthermore, the present disclosure is also applicable to a combinationin which the workpiece gear is a helical gear and the cutter is ahelical gear type cutter, or a combination of a workpiece gear ofanother shape and a cutter of another shape.

What is claimed is:
 1. A shaving processing method for finishing a toothsurface of a gear in a state where the gear and a shaving cutter areengaged with each other and the shaving cutter is rotated, the gearcomprising a pair of end surfaces facing each other in a tooth widthdirection, the method comprising: performing a first shaving step ofprocessing the tooth surface so that a processing region graduallyexpands from one end surface of the pair of end surfaces toward theother end surface; and performing a second shaving step of processingthe tooth surface so that a processing region gradually expands from theother end surface of the pair of end surfaces toward the one endsurface.
 2. The shaving processing method according to claim 1, whereinan intersection angle between a central axis of the gear and a centralaxis of the shaving cutter is set to a first intersection angle in thefirst shaving step and is set to a second intersection angle in thesecond shaving step, the first intersection angle is larger than thesecond intersection angle, and the second intersection angle correspondsto a finishing condition of the tooth surface.
 3. The shaving processingmethod according to claim 2, wherein an intersection angle between acentral axis of a shaft supporting the gear and a central axis of ashaft supporting the shaving cutter is set to the first intersectionangle in the first shaving step and is set to the second intersectionangle in the second shaving step.
 4. The shaving processing methodaccording to claim 2, wherein in the first shaving step, a first shavingcutter comprising a first cutting tooth extending in a directioncorresponding to the first intersection angle is used, and in the secondshaving step, a second shaving cutter comprising a second cutting toothextending in a direction corresponding to the second intersection angleis used.
 5. The shaving processing method according to claim 2, whereina rotational direction of the shaving cutter is switched to an oppositedirection during the second shaving step.
 6. A shaving processingapparatus for finishing a tooth surface of a gear in a state where thegear and a shaving cutter are engaged with each other and the shavingcutter is rotated, the gear comprising a pair of end surfaces facingeach other in a tooth width direction, the shaving processing apparatuscomprising an intersection angle adjusting mechanism which sets anintersection angle between a central axis of the gear and a central axisof the shaving cutter to a first intersection angle and to a secondintersection angle corresponding to a finishing condition of the toothsurface.
 7. The shaving processing method according to claim 1, whereinan intersection angle between a central axis of a shaft supporting thegear and a central axis of a shaft supporting the shaving cutter is setto the first intersection angle in the first shaving step and is set tothe second intersection angle in the second shaving step.
 8. The shavingprocessing method according to claim 1, wherein in the first shavingstep, a first shaving cutter comprising a first cutting tooth extendingin a direction corresponding to the first intersection angle is used,and in the second shaving step, a second shaving cutter comprising asecond cutting tooth extending in a direction corresponding to thesecond intersection angle is used.
 9. The shaving processing methodaccording to claim 1, wherein a rotational direction of the shavingcutter is switched to an opposite direction during the second shavingstep.